The present invention relates generally to medical devices and more particularly to a catheter for removing non-liquid material from a patient, such as a clot, thrombus or embolus from a vein.

One medical condition that affects a large number of patients is the formation of internal clots, thrombi and emboli within the vasculature. Some medical sources distinguish clots from thrombi and emboli. For example, a clot can be considered to be the initial stage of blood coagulation where blood forms a non-liquid mass due to reduced blood flow or other physiological conditions. A thrombus can be considered to be a more fibrous state of a clot where platelets and other cells aggregate to form a more solid mass. Oftentimes, a thrombus occurs where the collagen layer of a vessel becomes exposed since blood exposure to collagen encourages a cascade of clotting activity. However, numerous other factors can also encourage thrombus formation, such as hemodialysis grafts and certain drug treatments. A thrombus is generally considered to be a clotted mass that remains attached to a vessel wall, and is typically considered to be an embolus when the thrombus breaks loose from the vessel wall and flows through the vasculature. This can cause serious conditions because an embolus will often flow along the vasculature to a point where it obstructs downstream tissues, which can starve the obstructed tissues of blood and oxygen.

The seriousness of clotting formation and related events can vary from relatively minor conditions that are generally recoverable and/or treatable to life-threatening situations. For example, if the clotting involved is a short-term event and the individual is healthy, the vasculature may clear naturally without medical intervention. Hemodialysis patients with artificial fistulas may also suffer from thrombus formation within the fistula, which may require treatment or the surgical introduction of a new fistula. Deep vein thrombosis is another condition that can affect blood circulation within a patient's legs. This condition can start with mild symptoms of discomfort in the leg, but if left untreated thrombus formation can propagate throughout the patient's venous system and result in a life-threatening situation.

A number of methods for treating clots, thrombi and emboli have been tried. One method involves inserting a catheter so that the distal end of the catheter is close to the clot, thrombus or emboli. Suction is then applied to the lumen of the catheter to aspirate the vessel and suck the mass into the catheter and out of the vessel. However, the devices that are available for this treatment have various disadvantages. One concern is that any blood escaping from the catheter during use of the device should be minimized to reduce blood loss during the procedure. In addition, it can be difficult to remove non-liquid masses, like clots, thrombi and emboli, from some conventional catheters.

Aspects of the invention are set out in the appended claims.

In the following disclosure, a catheter is described with a seal and a collection chamber for removing non-liquid masses, such as clots, thrombi and emboli, from a patient's body while minimizing the risk of blood loss during the procedure. The catheter has a cap located proximal from the first seal that may be closed while the mass is aspirated into the collection chamber. The collection chamber is located between the cap and the first seal. During aspiration, the first seal is open to allow passage of the mass into the collection chamber. The first seal may then be closed to prevent fluid from escaping from the shaft lumen, and the cap is opened to permit removal of the mass. The cap may then be closed and the first seal reopened to collect additional masses.

The catheter may include a second seal that is provided in the cap. This second seal may be adapted to allow a guidewire to pass therethrough, while preventing fluid flow therethrough. The second seal may be a non-actuable seal. The second seal may be bidirectional and seal in response to pressure and suction. For example, the second seal may seal in response to pressure and suction applied to either side of the seal.

The collection chamber may define an axis that extends between said first seal and said openable cap. A length of the collection chamber may be from around 5 mm to around 50 mm. This length may, for example, be the length along the axis of the collection chamber. A cross-sectional area of the collection chamber may be larger than a cross-sectional area of the lumen. For example, the cross-sectional area of the collection chamber perpendicular to the axis of the shaft and/or to the axis of the collection chamber may be larger than a cross-sectional area of the lumen perpendicular to the axis of the shaft and/or to the axis of the collection chamber. The axis of the shaft may be parallel with the axis of the collection chamber; for example, the axis of the shaft may be aligned with the axis of the collection chamber.

The following disclosure also describes a method of removing a clot, thrombus or embolus from a vein, including: threading a catheter over a guidewire through an access site into a patient's vein, said catheter comprising a shaft with a lumen extending therethrough, a first seal, a second seal disposed in a cap and proximal from said first seal, a collection chamber between said first and second seals, and a suction port in communication with said collection chamber, said cap being closed, and said guidewire extending through said lumen, said first seal, said collection chamber and said second seal; removing said guidewire from said catheter by withdrawing said guidewire proximally through said lumen, said first seal, said collection chamber and said second seal; applying suction pressure to said suction port, said first seal being open, and said clot, thrombus or embolus passing through said lumen and said first seal and being received within said collection chamber; closing said first seal to prevent blood flow from said lumen into said collection chamber; and opening said cap and removing said clot or thrombus from said collection chamber.

The inventions herein may also include any other aspect described below in the written description, the claims, or in the attached drawings and any combination thereof.

The invention may be more fully understood by reading the following description in conjunction with the drawings, in which:

• Figure 1 is an elevational view of a catheter;
• Figure 2 is an elevational view of the catheter with the cap open;
• Figure 3 is an enlarged elevational view of the proximal portion of the catheter;
• Figure 4 is an end view of the catheter, showing the cap closed;
• Figure 5 is an end view of the catheter, showing the cap opened;
• Figure 6 is a cross-sectional view of the catheter, showing the cap closed and the first seal opened;
• Figure 7 is a cross-sectional view of the catheter, showing the cap opened and the first seal closed;
• Figure 8 is a perspective view of another embodiment of the catheter, showing the cap closed; and
• Figure 9 is a perspective view of the embodiment of Figure 8, showing the cap opened.

Referring now to the figures, and particularly to Figure 1, a catheter 10 is shown for collecting non-liquid masses, such as clots, thrombi, emboli or other masses. The catheter 10 is preferably used for collecting non-liquid masses from the vasculature and in particular the venous system. Thus, the catheter 10 is provided with a shaft 12 that extends through an access site into a patient's body. The access site typically provides access to the venous system, and the shaft 12 will extend through a vein so that the distal opening 14 of the shaft 12 is located next to the mass intended to be collected. Preferably, the shaft 12 is made of a flexible material like nylon or other polymers so that the shaft 12 can conform to the path of the vessel. The distal end of the shaft 12 is preferably atraumatic so that damage to the vessel wall is minimized. As illustrated in Figures 6-7, the shaft 12 is hollow with a lumen 16 extending from the distal opening 14 to the proximal portion of the catheter 10.

Along the proximal portion, the catheter 10 includes a first seal 18 that is capable of being closed to prevent fluid in the shaft lumen 16 from passing through the first seal 18 and escaping. Preferably, the first seal 18 can be actively controlled by the user so that the seal 18 can be actuated between a closed state and an open state. That is, the physician is able to open the first seal 18 and close the first seal 18 from outside the catheter 10 without pushing a device through the first seal 18. The first seal 18 may thus be thought of as a type of valve that can be closed to prevent fluid from escaping and opened when desired to allow the passage of medical devices and the mass to be collected.

A cap 20 is located proximally from the first seal 18, and a collection chamber 22 is defined between the cap 20 and the first seal 18. In Figure 1, the cap 20 is shown closed so that the cap 20 prevents fluid from escaping from the catheter 10. However, as shown in Figure 2, the cap 20 may be opened to provide access to the collection chamber 22. Preferably, the cap 20 is attached to the catheter 10 with a hinge 24 so that the cap 20 is not removable from the catheter 10. This allows the physician to open and close the cap 20 as desired without concern for dropping or misplacing the cap 20, which could make the cap 20 unsterile or could risk excessive blood loss. The cap 20 also preferably has a lip 21 that extends outward from the outer surface of the collection chamber 22 to allow the physician to easily grasp the cap 20 to open it. While the cap 20 may be oriented in various ways as desired, it is preferable for the cap 20 to extend across the axis of the catheter shaft 12 when it is closed. This allows straight access into the collection chamber 22 when the cap 20 is open to retrieve a collected mass. As shown in Figure 6, a snap 26, such as an o-ring 26 or other detent, may also be provided to keep the cap 20 closed and prevent the cap 20 from inadvertently opening. The snap 26 may also help in sealing the cap 20 when it is closed to prevent fluid like blood from escaping from the outside of the cap 20.

In use, suction is applied to a suction port 28 that is located along the collection chamber 22. As shown in Figure 1, a hose 30 may be attached to the suction port 28, and a valve 32 may be provided on the hose 30 if desired to open and close communication with the suction port 28. Various suction sources, such as a syringe or a vacuum machine, may be attached to the hose 30 or valve 32.

Alternatively, a valve could be provided in or adjacent to the suction port 28 and a suction source connected directly to the suction port 28 (though the suction source could use a hose for connection to the suction port 28). Such a valve might be actuable by the user, or might provide a non-actuable seal, opening in response to suction greater than a threshold amount (for example, having a magnitude greater than the pressure applied by fluid from the body within the collection chamber to the suction port 28) being applied to the suction port 28.

While suction is being applied to the suction port 28, the cap 20 is preferably closed and the first seal 18 is open as illustrated in Figure 6. As a result, blood and the mass intended to be collected passes through the distal opening 14 in the shaft 12 and through the shaft lumen 16. Since the first seal 18 is open, the material also passes through the first seal 18 and is received within the collection chamber 22. As shown in Figures 6-7, it may be desirable to provide a filter 29 in or adjacent to the suction port 28 to prevent the non-liquid mass from passing through the suction port 28. At this stage, the suction source may be shut off or the valve 32 closed to stop further suctioning. In order to remove the mass from the collection chamber 22, the first seal 18 is closed to prevent any additional fluid from escaping during the removal step. As illustrated in Figures 5 and 7, the cap 20 may now be opened without being concerned about additional blood escaping from the lumen 16 of the shaft 12. The material collected within the collection chamber 22 may then be removed through the cap opening 34. If desired, forceps may be inserted through the cap opening 34 into the collection chamber 22 to grasp the mass and pull it out of the collection chamber 22. Once the mass has been removed, the cap 20 may be closed, the first seal 18 opened, and suction applied to the suction port 28 again to collect additional material. This process may be repeated as needed to collect as much material as desired during the procedure. Between each collection step, the catheter shaft 12 may be moved through the vessel to relocate the distal opening 14 next to each mass intended to be collected.

The collection chamber 22 will preferably be of a sufficient size to collect a non-liquid mass, such as a clot, thrombus or embolus. Thus, the collection chamber 22 preferably has a cross-sectional area that is larger than the cross-sectional area of the shaft lumen 16. The cap opening 34 is also preferably large enough to insert forceps to grasp the collected material. Thus, the cap opening 34 preferably has a diameter of 10 mm to 30 mm. The collection chamber 32 is preferably also an elongate chamber 22 along the length of the axis of the shaft 12 so that passage through the cap opening 34, collection chamber 22 and shaft lumen 16 is generally straight. However, the collection chamber 22 need not be perfectly coaxial with the shaft lumen 16 and may have an offset shape as shown in Figures 8-9. The suction port 28 preferably extends from a side wall 36 of the collection chamber 22 so that the port 28 extends angularly from the chamber 22 with respect to the axis of the chamber 22. Thus, the suction port 28 does not interfere with the straight passage of the mass through the shaft lumen 16, first seal 18, collection chamber 22 and cap opening 34. Although the size of the collection chamber 22 may vary depending on the particular use of the device, a volume of 1 cc to 10 cc may be preferred to collect typical clots, thrombi and emboli. The length of the collection chamber 22 between the first seal 18 and the cap 20 is also preferably 5 mm to 50 mm.

Although various types of seals 18 are possible for the first seal 18, one type of seal 18 that may be used for the first seal 18 is illustrated in Figures 3 and 6-7. This type of seal 18 may have a bladder 38 that circumferentially surrounds a lumen 40 passing between the shaft lumen 16 and the collection chamber 22. The bladder 38 is typically made from a thin material 38 that can flex and squeeze in upon itself as illustrated in Figure 7 to close the seal 18. The bladder 38 may also flex outward to open the passageway 40 between the shaft lumen 16 and the collection chamber 22 as illustrated in Figure 6. Movement of the bladder 38 between the closed state and the opened state is controlled by pressure in the pressure chamber 42 between the outer surface of the bladder 38 and an outer wall 44 of the first seal 18. The outer wall 44 may be provided with a pressure port 46 to apply pressure to the pressure chamber 42 to control opening and closing of the bladder 38. As shown in Figure 1, a syringe 48 and a valve 50 may be connected to the pressure port 46 to apply pressure to the pressure chamber 42, and pressure may be retained to keep the first seal 18 closed by closing the valve 50. Although less desirable, other types of seals may also be used for the first seal 18, such as a seal with an elastic member that is directly squeezed by twisting an outer housing. A valve, such as a ball valve may also be used for the first seal 18.

It may also be desirable to provide a second seal 52 in the cap 20. The second seal 52 may be generally aligned with the lumen 16 of the shaft 12 to allow medical devices to extend through the catheter 10 while the cap 20 is closed. Thus, in the design of Figures 8-9, the second seal 52 is off-center in the cap 20 so that the second seal 52 is coaxial with the shaft lumen 16, since the collection chamber 22 is offset. For example, in typical intraluminal procedures, access to the vasculature will first be obtained using a guidewire that extends through the overlapping tissues and into a vein or artery. The proximal portion of the guidewire remains outside of the patient to provide a pathway through the patient's tissues into the vein or artery. Once access has been gained with a guidewire, the distal opening 14 may be threaded onto the guidewire, and the catheter 10 may be slid onto the guidewire so that the guidewire extends through the shaft lumen 16, the first seal 18, the collection chamber 22 and the second seal 52. The catheter 10 may then be threaded over the guidewire until the shaft 12 is located within the vein or artery. The guidewire may then be withdrawn from the catheter 10 by pulling the guidewire proximally through the second seal 52. During this stage of the procedure, the first seal 18 preferably remains open so that the first seal 18 does not interfere with passage of the guidewire. Since the cap 20 remains closed during introduction of the catheter 10 into the vasculature and the second seal 52 seals against the guidewire, blood will not escape even if the first seal 18 is open. Unlike the first seal 18, the second seal 52 may be a non-actuable seal 52, in that the second seal 52 passively seals and does not need to be separately controlled between an opened and closed state. Thus, the second seal 52 may be biased toward the closed state. Where the second seal 52 is passive, it is preferable for the second seal 52 to be bidirectional so that it seals both when suction is applied to the collection chamber 22 and when blood pressure exists in the collection chamber 22. Thus, as shown in Figure 6, the second seal 52 extends perpendicular to the axis of the shaft lumen 16 and is not biased in either the proximal or distal direction.

While preferred embodiments of the inventions have been described, it should be understood that the inventions are not so limited, and modifications may be made without departing from the inventions herein. While each embodiment described herein may refer only to certain features and may not specifically refer to every feature described with respect to other embodiments, it should be recognized that the features described herein are interchangeable unless described otherwise, even where no reference is made to a specific feature. It should also be understood that the advantages described above are not necessarily the only advantages of the inventions, and it is not necessarily expected that all of the described advantages will be achieved with every embodiment of the inventions. The scope of the inventions is defined by the appended claims, and all devices and methods that come within the meaning of the claims, either literally or by equivalence, are intended to be embraced therein.